The present invention relates to a sealing apparatus and method of sealing a moveable filtering medium and more particularly to an improved apparatus and method for filtering particulate materials from a dirty fluid stream which is passed through a flight of an endless filter medium belt or a strip of continuously fed filter medium with a portion of the recirculated clean fluid being utilized along the side edges of the filter medium for sealing.
In the prior art, U.S. Pat. No. 4,159,948, issued to William D. Crowe on Jul. 3, 1979, the broad principle of sealing the side edges of a filter belt with clean fluid recirculated from a reservoir below the filter medium treating sight for a dirty fluid stream is disclosed, attention being particularly directed to FIGS. 4 and 5 of this patent. However, in this patent the filter medium is advanced by an indexed pinch roller and the clean fluid is applied to the filter medium through spaced grooves in side edge sealing members immediately adjacent the side edges of the filter medium. The cleaning operation of the side edges in this patent is accomplished through a comparatively complex control arrangement during down-time of filtering operations. Further, a substantial wear on the filter medium side edges occurs through the recirculated water receiving grooved side edge sealing members and the accompanying pulling forces exerted on the filter medium by the pinch rollers. In later issued patents, such as U.S. Pat. No. 4,390,428, issued to Jack R. Bratten on Jun. 28, 1983, which teaches the utilization of an inflatable seal tube abutting the side edges of an endless filter belt, and U.S. Pat. No. 4,421,647, issued to Mark R. Estabrook et al on Dec. 20, 1983, which teaches sealing the side edges of filter medium by forcing the side edges of the medium into grooves, similar filter medium wear problems have occurred, along with the required utilization of comparatively complex structures to accomplish the medium sealing. Even in later U.S. Pat. No. 4,481,108 and U.S. Pat. No. 5,601,729, issued to Jack R. Bratten on Nov. 6, 1984 and Feb. 11, 1997, respectively, the use of disclosed wear inflicting, inflatable sealing tubes has been relied upon for sealing side edge sealing of filter medium, necessarily resulting in the aforedescribed undue wear of the filter medium. Also in these aforementioned patents the major problem of solids bypassing the medium from the dirty to the clean side of the system, occurs during the indexing movement of the filter medium when the sealing tubes have been deflated to permit filter medium movement.
The present invention recognizing certain of the problems recognized by the prior art, as well as problems created by prior art solutions, avoids the same with a unique structure and method which is straightforward and economical in construction, operation and maintenance-requiring a comparative minimum of parts and a comparative minimum of steps in resolving prior art difficulties. Further, the present invention uniquely utilizes the sealing machinery itself, to further supplement the novel sealing arrangement of the present invention.
Various other features and advantages of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein.